This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-360151, filed Dec. 20, 1999, the entire contents of which are incorporated herein by reference.
This invention relates to a coating processing apparatus for coating a coating solution such as a resist solution on the surface of a liquid crystal display device (LCD) substrate and a semiconductor substrate.
In manufacturing a liquid crystal display (LCD), a circuit pattern is formed by a so-called photolithography in which a rectangular LCD substrate made of glass is coated with a photo resist solution to form a resist film, the resist film is exposed in accordance with the circuit pattern, which is subjected to a developing processing. A resist coating and developing system including a plurality of processing units for performing a series of processings like these has been hitherto used.
In the resist coating and developing system like this, the rectangular LCD substrate is subjected to a hydrophobic processing (HMDS processing) in an adhesion processing unit in order to increase an adhering property of the resist, cooled in a cooling unit, and then carried into a resist coating unit in the process of coating a resist solution. In the resist coating unit, the substrate is rotated while being held on a spin chuck, the resist solution is supplied from a nozzle provided thereon to the surface of the substrate, the resist solution is diffused by centrifugal force by the rotation of the substrate, and thus the resist film is formed on the entire face of the substrate.
The substrate coated with the resist solution is rid of the excess resist in the peripheral edge in an edge surface processing unit (edge remover), carried into a heating unit to be subjected to a prebaking processing, cooled in the cooling unit, carried into an aligner where an exposure is performed in accordance with a predetermined pattern, and subjected to the developing and a postbaking processing to form a predetermined resist pattern.
Regarding to the aforesaid resist coating, a method of dropping the resist solution at the almost center of the substrate provided inside a cup, and then rotating the substrate at high speed to diffuse and coat the resist solution by centrifugal force has conventionally been known.
The resist film with uniform film thickness over the entire face of the substrate can be obtained to a certain extent by the aforesaid method, however, there is a possibility that an ununiformity of the local film thickness such as the thicker film thickness in the center part of the substrate may occur by the influence of the temperature, humidity and so on. When the ununiformity like this occurs, the film thickness is adjusted by controlling the temperature and the humidity inside the cup, but the film thickness is not necessarily adjusted enough, and therefore a means for effectively adjusting the film thickness after the resist solution is coated is required.
An object of the present invention is to provide a coating processing apparatus which can effectively perform the adjustment of a film thickness of a coating film after a coating solution is coated.
To solve the aforesaid problem, according to a first aspect of the present invention, a coating processing apparatus for coating a coating solution onto the surface of a substrate, comprising: a processing container having an opening portion on the top thereof for housing the substrate, a substrate rotating member for rotating the substrate in the processing container, a coating solution discharge nozzle for discharging the coating solution onto the substrate, and an airflow forming portion for forming an airflow which can adjust a film thickness of the substrate in the processing container.
According to a second aspect of the present invention, a coating processing apparatus for coating a coating solution onto the surface of a substrate, comprising: a processing container having an opening portion on the top thereof for housing the substrate, a lid body attached to the processing container, a substrate rotating member for rotating the substrate in the processing container, a coating solution discharge nozzle for discharging the coating solution onto the substrate, and an airflow forming portion for forming an airflow which can adjust a film thickness of a coating film in the processing container.
According to the first aspect and the second aspect, the airflow forming portion for forming the airflow which can adjust the film thickness of the substrate is provided in the processing container so that the variation of the coating film thickness by the change of the temperature of the coating solution or the like can be decreased and the film thickness of the coating film can be adjusted. That is, according to the experimental result by the present inventors, the film thickness of the coating film changes by forming the airflow in the processing container so that it is found out that the film thickness can be adjusted by forming a desired airflow corresponding to a profile of the film thickness to be formed and thus a uniform film thickness can be obtained, which resulted in the accomplishment of the present invention.
For example, when the lid body is provided to be attached to the processing container and the film thickness of the coating film is adjusted with the lid body attached, it is easier to obtain the uniform film thickness compared with the case without the lid body, nevertheless the film thickness in the center of the substrate, for example, becomes thicker. In this case, a protrusion member as the airflow forming portion is formed at a predetermined position in the underneath surface of the lid body so that the airflow can be formed by the protrusion member at the predetermined position in the processing container when the lid body is rotated with the substrate and the processing container, which makes it possible to adjust the film thickness. For example, the protrusion member is formed in the center of the underneath surface of the lid body so that the airflow can be formed in the center part of the processing container and the film thickness in the center part can be adjusted. Thus, the coating film with the uniform film thickness can be obtained.
Further, in either case where the lid body is attached/not attached to the processing container, the airflow can be formed at the predetermined position in the processing container by providing a ventilating means as the air flow forming portion at the predetermined position directly above the substrate inside the processing container to form the airflow, which makes it possible to adjust the film thickness to obtain the coating film with uniform film thickness.
According to a third aspect of the present invention, a coating processing apparatus for coating a coating solution onto the surface of a substrate, comprising: a processing container having an opening portion on the top thereof for housing the substrate, a substrate rotating member for rotating the substrate in the processing container, a lid body having an opening and attached to the processing container, a coating solution discharge nozzle for discharging the coating solution onto the substrate through the opening of the lid body, a small lid for blocking up the opening of the lid body, a small lid carrier means for carrying the small lid to attach the small lid into the opening of the lid body, and a protrusion member provided on the underneath surface of the small lid to be positioned inside the processing container when the small lid is attached into the opening of the lid body.
The aforesaid third aspect of the present invention includes the lid body having the opening and the small lid for blocking up the opening so that the coating solution is discharged from the coating solution discharge nozzle through the opening of the annular lid body, and the small lid is attached into the opening of the annular lid body after the coating solution is discharged to thereby adjust the film thickness. Therefore, when the solution is discharged, the scatter of the coating solution to the outside can be prevented with the annular lid body even when the substrate is rotated while the coating solution is discharged, which is so-called a dynamic coating method, and after the coating solution is discharged, the scatter of the coating solution to the outside can be prevented with the annular lid body and the small lid, and thus the scatter of the coating solution can be securely prevented from the start of the coating to the end.
However, in the apparatus like this, the coating solution discharge nozzle is normally inserted from the opening in the center of the lid body and the resist solution as the coating solution is discharged from the coating solution discharge nozzle to form the resist film on the substrate, in the meantime, the drying in the area which corresponds to the opening of the coating film progresses faster and a peculiar region of the airflow is likely to be formed in the area which is right under the opening of the processing container, that is in the center part. Therefore, when the film thickness is adjusted by rotating the substrate with the small lid attached, there arises a problem that the film thickness of the resist film in the center part of the substrate becomes thicker.
Meanwhile, as described above, the protrusion member is provided on the underneath surface of the small lid to position the protrusion member inside the processing container when the small lid is attached into the opening of the lid body so that the film thickness of the coating film such as the resist film can be adjusted by forming the airflow inside the processing container when the processing container, the lid body and the small lid are rotated with the substrate, and the coating film with uniform film thickness can be obtained.
These objects and still other objects and advantages of the present invention will become apparent upon reading the following specification when taken in conjunction with the accompanying drawings.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.